Tap-changer mechanism



Nqv. 19,1929. K. A. OPLINGER ET AL 1,736,459

' I TAP CHANGER MECHANISM v Filed Nov. 19.1926 5 sheets-sheet 1 Fig. I.

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; Nov. 19, 1929. K. A OPLINGER ET AL TAP CHANGER MECHANISM Fild Nov. 19, 1926 5 Sheets-Shet 2 I l i I 1 Shgets-Sheet 5 INVENT OR5 Kirk AOp/mger 82 TORNE Leland HLHI'H. a

K. AQOPLINGER ET AL TAP CHANGER MECHANISM Filed Nov. 19, 1926 Nov'..19, 1929.

Fig. 3.

Patented Nov. 19, 1929 UNITED STATES PATENT OFFICE KIRK A. OPLINGEB. AND LELAND H. HILL, OF SHARON, PENNSYLVANIA, ASSIGNORS T0- WESTINGHOUSE ELECTRIC AND OF PENNSYLVANIA MANUFACTURING COMPANY, A CORPORATION TAP-CHANGER MECHANISM Application filed November 19, 1926. Serial No. 149,309.

Our invention relates to electrical transformers and particularly to transformer tapchanger mechanisms.

One object of our invention is to provide a manually operable tap-changer mechanism that shall be inaccessible when the associated transformer is electrically energized.

Another object of our invention is to provide an interlock between a circuit interrupter for connecting a transformer to an electrical. circuit and a tap-changer mechanism for the transformer that shall preclude the operation of'the tap-changer mechanism while the circuit interrupter is in its closed position.

Another object of our invention is to provide a housing for a tap-changer mechanism that shall be held open so long as the tapchanger is in an intermediate position relative to the terminals of the transformer winding.

Another object of our invention is to provide a housing for a tap-changer mechanism that shall be kept closed by combined electrical means.

A further object. of our invention is to provide a manually operable tap'changer mechanism for a transformer that shall be rendered inaccessible so long as an associated circuit interrupter is in its closed position and an associated lock is in its locking position.

In the operation of manually-actuated tapchanger mechanisms for transformers, there is an ever,present danger that the tap connections may be shifted While the transformer is electrically energized. [he operation of a tap-changer mechanism, under such conditions, results in the development of voltage surges, in the winding of the transformer,

which are liable to cause a breakdown. We

propose to so interlock the tap-changer mechanism with a circuit interrupter that controls the energization of the associated transformer that the tap-changer mechanism shall be precluded from operation so long as the circuit interrupter is in its closed position, thereby rendering it impossible for an operator to vary the winding connections of a transformer while it is electrically energized,

and, with the circuit interrupter in open pocasing 13 inclosing the transformer 1.

sition,- it is impossible to close it unless the tap-changer is in proper position.

In the accompanying drawings,

fFigure 1 is a view, partially in elevation and partially in section, of a portion of a transformer equipped with our improved tapchanger mechanism.

Fig. 2 is a broken view, in elevation, of a casing containing the actuating mechanism for the tap-changer mechanism, together with the mechanical features of the interlocking mechanism.

Fig. 3 is a view, partially in elevation and partially in section, of the actuating and interlocking mechanisms taken along the section line III-III of Fig. 2.

Fig. 4 is an elevational view of the positioning and indicating details of the tapchanger mechanism.

Fig. 5 is a view, partially in elevation and partially in section, of the positioning and indicating details of the tap-changer mechanism, taken along the section line VV of Fig. 6 is a horizontal sectional view taken on the line VI-VI of Fig. 3, and,

Fig. 7, is a diagrammatic view of the circuits and apparatus embodying our invention. I

Referring particularly to Figs. 1 and 7, our invention comprises, in general, a transformer 1 having a plurality of terminals 2, the connection of which is varied by a tapchanger switch 3 that, in turn, is connected by a linkage mechanism 4 to a hand wheel 5, access to which is controlled by a door (3 of a casing 7 that is electrically interlocked with the tripping and closing electromagnets 8 and 9, respectively, of a circuit interrupter 10 that connects the transformer 1 to an electrical circuit 11.

Referring to Fig. 1, the elements 1 to 4:, inclusive, of the invention, may be of any preferred form suitable for completing the combination of parts hereinafter more fully described. llhe hand-wheel 5 is provided with a single notch 12 in its periphery that co-operates with a lug 12 on the inside of the door 6. The casing 7 is mounted upon the 1e door 6 is provided with a pair of handles 14 and is supported by hinges 15 from the casing 7. The barrels of two locks 16 and 17 extend outwardly through the door 6.

Referring particularly to Figs. 2 and 3, the bolt 18 of the lock 16 engages a plate 19 mounted within the casing 7 for retaining the door 6 in its closed position. The lock 16 is provided also with an auxiliary cam 21 that bears against a lever 22 that, in turn, bears against a push button 23 protruding from a switch 24 that is mounted on a panel 25 within the casing 7.

Referring to Figs. 2, 3 and 6, a bolt 26 of the lock 17 engages akeeper 27 that is secured by a hinge 28 to a frame that is mounted on the outer face of the panel 25. An electromagnet 31 is mounted within the frame 29, and its armature 32 is attached to one end of a lever 33, the other end of which extends into a hole 34 in the keeper 27. Accordingly, the lock 17 holds the door 6 in its closed position through its bolt 26, keeper 27 frame 29 and the panel 25. The switch 24 is in series connection with the electromagnet 31.

The panel 25 supports a second switch 35 that is provided with a ush button 36 for cooperating with an a justable screw 38 mounted interiorly of the door 6. The switch 35 is held in closed position by the door 6 when the latter is closed, and is connected in series with the closing electromagnet 9 of the circuit interrupter 10 in order that the circuit interrupter 10 may not be closed so long as the door 6 is open.

Referring to Figs. 2 to 5, inclusive, the

, hand wheel 5 is mounted at the lower end of a shaft 38 that constitutes a portion of the linkage mechanism 4. A single-toothed bevel gear 39 is mounted on the shaft 38 within a housing 40 through which the shaft 38 extends. The gear 39 drives a second intermittent gear 41 that is supported from the frame 40 by a collar 42 through which the shaft 38 extends. An index plate 43 is secured to the outer face of the bevel gear 41, and the indices mounted thereon are successively displayed before a window 44 that is provided in the outer wall of the frame 40. The gear 39 is turned through a complete revolution for each change of the transformer connections, while the number of teeth on the gear 41 corresponds to the total number of operative positions of the switch 31. Accordingly, the position of the tap-changer switch 3 may be ascertained by an inspection of the index appearing in the window 44.

The hub for the gear 39 is provided with a plurality of downwardly extending slots 45 that are engaged by a trigger 46 which is pivotally mounted, as at 47, on the frame 40. A push button 48, that constitutes the other end of the trigger 46, extends outwardly from the frame 40. A spring 49 serves to bias the trigger 46 toward engagement with one of the slots 45. The trigger 46 and the frame'40 are provided with aligned openings 51 for the reception of a padlock should it be desired to lock the shaft 38 in a fixed position. By reason of the presence of the trigger 46, the operator must depress the push button 48 before the shaft 38 may be turned, thereby preventing accidental movement of the tapchanger switch 3. Referring to Fig. 7, the tripping electromagnet 8 is provided with a back contact 55 that is in series connection with the electromagnet 31 and the switch 24 between the conductors of the circuit 11. It is to be understood that the tripping and closing electromagnets 8 and 9, respectively, may be controlled by' a source of electromotive force separate from the circuit 11, if so desired. The closing electromagnet 9 is connected in a circuit extending from one of the conductors of the circuit 11, through the closing electromagnet 9, a push-button switch 56 and the switch 35, to the other conductor of the circuit 11. The tripping electromagnet 8 is included in a circuit extending from one of the conductors of the circuit 11, through a pushbutton switch 57 and the electromagnet 8, to the other conductor of the circuit 11.

Assuming the transformer to be in operation and the circuit interrupter 10 to be in its closed position, and it is desired to change the ratio of the transformer 1 by varying its tap connections between the terminals 2 and the switch 3; the operator closes the switch 57, thereby energizing the electromagnet 8 the circuit interrupter 10 to its open position for deenergizing the transformer 1.

During the opening operation of the circuit interrupter 10, the back contact 55 completes a circuit from one of the .conductors of the circuit 11, through the contact 55 and the electromagnet 31, to the switch 24 which is still open. The operator then inserts his key in lock 16 and turns it to withdraw the bolt 18 from behind the plate 19, at which time the cam 21 is turned to cause the lever 22 to close the switch 24. The closure of the switch 24 completes the circuit from the electromagnet 31 to the second conductor of the circuit 11.

The energization of the electromagnet 31 turns lever 33 to disengage it from the hole 34 in the keeper 27, after which a pull on the handles 14 permits the door 6 to be opened by reason of the keeper 27 turning about its hinge 28 to permit the bolt 26 of the lock 17 to escape from behind it.

Should the electromagnet 31 fail to be electrically energized, the operator may secure the key to the lock 17 andwithdraw the bolt 26 from behind the keeper 27. The key for the lock 16 is normally left with a'power-house attendant while the key to the lock 17 should be left with a supervising ofiicial to be surrendered only when he is satisfied that the transformer 1 is deenergized.

After the door 6 has been opened, the padlock is removed from the openings 51, it necessary; the operator depresses the push-button 48 and turns the hand wheel 5 until the desired index, corresponding to the desired tap position, appears in the window 44, after which the o erator releases the push-button 48 and locks the trigger 46 in pesit-ion, it desired.

The door 6 is then closed, it the notch 12 and the lug 12 are in registry to show that the switch 3 is closed, and the bolts 18 and 26 return to, their locked positions, whereupon the circuit of the electromagnct 31 is broken by the switch 24.

The closing of the door 6 closes the switch 35, so that, when the switch 56 is depressed, a circuit for the closed electromagnet 9 is completed, and the circuit interrupter 11 is closed to again energize the transformer 1.

It will thus be seen that we have provided an interlock for manually-operated tapchanger mechanism that prevents the operation of each mechanism until after a' circuit interrupter, connecting the transformer to a source of electromotive force, has been opened and one lock has been manually operated. The operation of the first lock completes the circuit for an interlock with the second lock, after which the door of a casing, housing a part of the tap-changer mechanism, may be opened to gain access to the mechanism. Provision is also made for preventing the operation of the closing electromagnet of the circuit interrupter while the door of the casing is open.

\Vhile we have shown and described a specific form of our invention, changes may be effected therein without departing from the spirit and scope thereof, as set forth in the appended claims.

We claim as our invention:

1. The combination with an electrical winding having a plurality of terminals, means for varying the-electrical connections of the terminals, and actuating means for the first named means, of acasing for housing at least a portion of the actuating means, a closure member for the casing and means in electrical circuit with the winding for controlling the operation of the closure member.

2. The combination with an electrical winding having plurality of terminals, means for i 'arying the electrical connections of the terminals, and' actuating means for the first named means, of a casing for housing at least a portion of the actuating means, a closure member for the casing and electrically controlled means for controlling the operation of the closure member.

3. The combination with an electrical winding having a plurality of terminals,

means for varying the electrical connections of the terminals and actuating means for the first named means, of a casing for housing at least a portion of the actuating means, a closure member for the casing and means both electrically and mechanically controlled for controlling the operation of the closure memher.

4. The combination with an electrical winding having a plurality of terminals, means for varying the electrical connections of the terminals and actuating means for the first named means, of a casing for housing at least a portion of the actuating means, a closure member for the casing and electrical- 1y controlled means for preventing an opening movement of the closure member while the winding is electrically energized.

5. The combination with an electrical winding having a plurality of terminals, means for varying the electrical connections of the terminals and actuating means for the first named means, of a casing for hous ing at least a portion of the actuating means, a closure member for the casing and means, both electrically and mechanically controlled, for preventing opening movement of the closure member while the electrical winding is energized.

6. The combination with an electrical winding having a plurality of terminals, means for varying the electrical connections of the terminals, a circuit interrupter for controlling the energization of the winding and actuating means forthe connection varying means, of a casing for at least 'a portion of the actuating means, a closure member for the casing and means, interconnected with the circuit interrupter, for controlling the operation of the closure member.

7. The combination with an electrical winding having a plurality of terminals, means or varying the electrical connections of the terminals, a circuit interrupter for controlling the energization of the winding and actuating means for the connection-varying means, of a casing for at least a portion of the actuating means, a closure member for the casing and means, interconnected with the circuit interrupter, for preventing the opening of the closure member while the circuit interrupter is in its closed position.

8. The combination with an electrical winding having a plurality of terminals, means for varying the electrical connections of the terminals, a circuit interrupter for controlling the energization of the Winding and actuating means for the connection varying means, of a casing for at least a portion of the actuating means, a closure member for the casing and means, comprising a mechanically operated member and an electrically controlled member, that is interconnected with the circuit interrupter for con: trolling theoperation of the closure member.

9. The combination with an electrical winding having a plurality of terminals, means for varying the electrical connections of the terminals, a circuit interrupter for controlling the energization of the winding and actuating means for the connection varying means, of a casing for at least a portion of the actuating means, a closure member for the casing and means, comprising a mechanically controlled member and an electrically controlled member, for controlling the operation of the closure member, the energization of the electrically controlled member being dependent upon the positions of the circuit interrupter and the mechanically-controlled member.

10. The combination with a transformer, a tapchanger mechanism therefor and an electromagnetically closed circuit interrupter for controlling the energization of the transformer, of a casing for the tap-changer mechanism having a closure member and interconnecting means between the closure means and the closing electromagnet for rendering the latter inoperative when the closure member is in its open positions.

11. In a tap-changer mechanism, a housing for a portion of the mechanism comprising a door, a transformer winding having a plurality of terminals,a switch for controlling the connections of the terminals and actuated by the mechanism, and means for preventing the closing of the door when the switch is in its open positions.

12. In a tap-changer mechanism, a housing for a portion of the mechanism comprising a door, a transformer winding having a plurality of terminals, a switch for controlling the connections of the terminals and actuated by the mechanism, an interlock between the door and the mechanism for preventing the closing of the door while the switch is in its open position.

In testimony whereof, we have hereunto subscribed our names this 12th day of November, 1926.

KIRK A. OPLINGER. LELAND H. HILL. 

